COMP Report: Patient-specific quality assurance practices in Canadian radiotherapy-results from a national survey.

Patient-specific quality assurance (PSQA) is an essential component of modern radiotherapy, ensuring safe and accurate delivery of increasingly complex treatments. Given its resource-intensive nature and the availability of evolving approaches, examining how PSQA is implemented and optimized across Canada is important to inform best practices. This study aimed to characterize the current landscape of PSQA practice across Canadian radiotherapy centers, identify patterns and regional variations, and explore opportunities for future national guidance. A 30-question web-based survey was developed and distributed in March 2024 to all Canadian radiotherapy centers, including satellites. The survey addressed staffing, treatment machines, PSQA tools and methodologies, policies, data analysis, frequency of PSQA, and failure management. Responses were collected in both English and French, de-identified, and analyzed by center size and region (British Columbia, Prairies, Ontario, Quebec, and Atlantic). The survey achieved a 90% response rate (45 of 50 centers). Most centers reported using 3D array detectors, followed by EPID and point detectors. Gamma index analysis was the predominant evaluation method. More than half of participating centers, including 65% of large centers, reported reducing PSQA measurement frequency, citing accumulated local experience rather than external guidance. However, all centers in the Prairies and Atlantic regions reported maintaining full measurement frequency. A vast majority of centers that used delivery log calculations also reported a reduction in measurement frequency, while most centers using EPID did not. Across all regions, selective adoption of recommendations from both Canadian and American guidelines was observed. PSQA practices in Canada are heterogeneous, reflecting local resources, institutional experience, and evolving international recommendations. Given the resource-intensive nature of PSQA and observed variability in practice, these findings highlight the value of developing national guidance tailored to Canadian clinical realities.